1. Field of the Invention
The invention generally relates to an image processing technique, in particular, to a method, an image processing apparatus and a computer readable medium for image enhancement.
2. Description of Related Art
Along with the fast development in LCD-TVs, ultra-high definition (UHD) LCD-TVs have become emerging technologies mainly due to advantages such as high contrast, high brightness, high color saturation, and wide viewing angles. UHD LCD-TVs provide tremendous market potential for large-size LCD panels and deliver luxurious visual experiences by a display technology capable of exceeding the limits of human perception.
However, since UHD image capturing apparatuses are still underdeveloped, super resolution images are not commonly available. The so-called “super-resolution image” may be obtained by upscaling an image and compensating for the loss of high-frequency information so that the upscaled image may still preserve the clarity or even provide more details than the original image. Such technique is widely-adopted for TV signal image processing to convert low-resolution original signals to images with high quality.
The prior art methods may use a database as a reference source for a high-resolution image or a complex iteration process such as self-example based method to generate a super-resolution image. Such approaches may create significant results, and yet may not be feasible for real-time implementation on a video display chip. On the other hand, a super-resolution image with local contrast enhancement may be generated by leveraging some conventional image sharpening methods, where in particular, the unsharp masking sharpening method with high efficiency and low complexity is suited for real-time video application. Nevertheless, the generated image may be degraded due to ringing or jaggy artifacts occurring during a conventional unsharp masking sharpening process.